The present invention relates to an actuator device comprising a flexible cable, which has one end connected to a controlled member, and a flexible sheath, inside which is mounted the flexible cable, in which at least one portion of the flexible cable consists of a shape-memory material, which is able to undergo a variation of shape following upon its heating, in order to control the controlled member.
Flexible-cable actuator devices find their application in a wide range of fields and in general wherever it is necessary to provide a mechanical transmission which is simple and inexpensive and will enable remote control of the displacement of a member. Flexible-cable actuator devices are, for example, used for providing manual-control actuations on motor vehicles, for example for release from inside of the rear hatchback or of the bonnet, or for actuation of mobile parts or of mechanisms of seats of motor vehicle, or for the actuation of mobile members of the engine or of facilities on board the motor vehicle. There is moreover known a wide range of applications also outside the automobile field.
A flexible-cable actuator device having the characteristics referred to at the start of the present description is known from the document DE-C-199 16 244. Said known device is designed to be controlled manually in all conditions of use. However, its actuation brings about an activation of the shape-memory element, with the consequence that the controlled member undergoes an additional displacement with respect to the one brought about by mere manual actuation.
In the prior Italian patent application No. TO2001A000618, filed on Jun. 27, 2001, and in the corresponding internal patent application PCT/IB02/02361, the present applicant has proposed an actuator device comprising:                a flexible cable having one end connected to a controlled member, and        a flexible sheath inside which is mounted the flexible cable,        in which at least one portion of the flexible cable consists of a shape-memory material which is able to undergo a variation of shape following upon its heating in order to control the controlled member,        in which the aforesaid sheath is mounted with respect to a fixed supporting structure so as to be free to be displaced longitudinally only in a direction corresponding to the direction of actuation of the controlled member, and        in which, moreover, the aforesaid sheath is coupled to the controlled member so as to be able to transmit directly thereto a displacement in the aforesaid direction of actuation and to be, instead, uncoupled by the controlled member in the event of a movement in the opposite direction, in such a way that said actuator is able to be used both manually, as element of mechanical transmission, using the sheath as element of transmission, and exploiting the variation of shape of the shape-memory cable, which can be obtained with its heating. The heating can be obtained by causing passage of electric current through the shape-memory cable.        